Nutrients 101 for Oakland Bay and Lessons Learned from Hood Canal Science Review. Mindy Roberts Washington State Department of Ecology 12/5/12

Transcription

1 Nutrients 101 for Oakland Bay and Lessons Learned from Hood Canal Science Review Mindy Roberts Washington State Department of Ecology 12/5/12 1

2 Presentation Overview Nutrients 101 How are nutrients, dissolved oxygen, and algae related? Hood Canal science review highlights Mainstem of Hood Canal Fish kill region Lower Hood Canal/Lynch Cove Applications to Oakland Bay *Draft* ideas for your consideration and discussion 2

3 oxygen oxygen sunlight nitrogen nitrogen nitrogen nitrogen Why reduce nutrients when we care about dissolved oxygen? wind Mixed upper layer Isolated lower layer Budd Inlet watershed Puget Sound phosphorus or Capitol Lake or Deschutes River (phosphorus)

4 Report Focus: Nitrogen, Algae, and Dissolved Oxygen 4

5 nitrogen algae low dissolved oxygen Human Natural Marine (Marine) EPA/Ecology regulatory question: Are humans causing the dissolved oxygen to worsen by >0.2 mg/l? 5

6 Marine dissolved oxygen water quality standards DO > 7.0 mg/l in HC (>6.0 mg/l in OB) All times of year Any location in water column If naturally < 7.0 mg/l, then total human impact to DO must be < 0.2 mg/l All times of year Any location in water column Point + nonpoint sources Regulatory question: How much nitrogen from humans? Circulation governs sensitivity to nitrogen

7 Local + ocean Source: Mackas and Harrison (1997) nitrogen

8 RIVERS WWTPs Local DIN

9 So what s this about Hood Canal? 9

10 Hood Canal Effective Management Actions Public Stakeholder Review EPA/Ecology Science Summary Paid Independent Peer Review PNNL sediment cores UW Civil aggregated model Hood Canal Dissolved Oxygen Program USGS groundwater and nearshore Mason County seep monitoring Independent $$ Independent $$ Funding: ~$7m (US Navy) UW Ocean marine monitoring UW Civil river monitoring UW Ocean aggregated models UW Civil aggregated model UW Ocean ROMS model HCSEG, Skokomish, biota Duration: Independent $$ 10

11 Peer Review Process Drafts March 2011 June January 2012 August September

12 EPA/Ecology major findings No significant human contribution to low dissolved oxygen Fish kills Dissolved oxygen conditions have not worsened compared to pre-1900 conditions. Fish kills caused by natural circulation and wind events Inconclusive Higher impacts, but do not know if violating water quality standards SHCDOP/hc-dem.jpg 12

13 More information on key findings 1. Sediment cores and historic conditions 2. DO trends 3. Central Hood Canal conditions and fish kills 4. Analysis of Lynch Cove impacts 5. Next steps 13

14 1. Sediment cores (PNNL) Low-oxygen conditions before European settlement Oxygen lower before 1900 than between 1900 and 2005 Contrary to expected pattern Low-oxygen follows a decadal pattern Suggests climate influences are dominant in large basins Source: PNNL 14

15 1. Sediment cores low dissolved oxygen and climate Climate indicator Humans? Oxygen indicator Source: PNNL/ Brandenberger et al. 15

16 2. Dissolved oxygen trends (1950s to 2000) Declining trend not unique to Hood Canal No declining trend in Lynch Cove, where oxygen levels are lowest Hood Canal DO DO in Seattle, Admiralty Inlet, Straits Lynch Cove DO Source: UW Applied Physics Laboratory 16

17 3. Fish kill conditions Wind Higher DO surface water Anoxic water Lynch Cove Fall intrusion Central Hood Canal 17

18 3b. Why are impacts very low in central Hood Canal? Human Contribution: Human Natural Marine (Marine) Source: USGS (2006) and Steinberg et al. (2010) 18

19 4. Impacts in Lynch Cove Lowest circulation and marine nitrogen Highest population Researchers task Add up all the nitrogen loads Ideas for OB? Rainfall Red Alder Natural Background Marine Upwelling Human Population 19

20 Frequency 90 Most samples 80 < 1 mg/l 70 (good) Nitrogen in shoreline seeps 325 samples Few samples >2 mg/l (not good) More Dissolved Inorganic Nitrogen (mg/l) Data collection: Mason County Data sorting: Sheibley, pers. comm. (2011) and EPA/Ecology Plot: EPA/Ecology 20

21 60-80 mg/l nitrogen Most <1 mg/l *variable* 21

22 Pollution Identification and Correction (PIC) Problem: Very high nitrogen/bacteria values Some high values are from failing OSS Examples where concentrations drop after repair Shellfish beds re-opening in Lynch Cove Confirms need to find and repair failing septics for multiple benefits, including bacteria Source: Georgeson et al. (2008) 22

23 How much do human sources impact dissolved oxygen? what s the marine nitrogen loading Human Natural Marine (Marine) 23

24 UW Oceanography Devol, Warner, Newton UW Civil/Environmental Engineering Steinberg, Brett UW Oceanography Kawase UW Oceanography measurements? Lynch Cove marine nitrogen loading 5 37* 78 >150 Bigger human impact Smaller human impact Independent reviewers: Information available is insufficient to estimate the marine nitrogen loading to Lynch Cove Try this way EPA/Ecology range 24

25 Frequency EPA and Ecology s Best Estimate from Box Model Summer average DO impact in Lynch Cove mg/l Uncertainty is high, results are inconclusive uncertainty in marine N Lynch Cove DO Impact highly generalized time and space scales model too simple? % % % % Paid Independent Peer Review % 20.00% 0.00% DO (mg/l) 25

26 Alternative tool: ROMS model Second line of evidence Sophisticated tool 3D simulation Model calibration (accuracy) issues Simplified scenario setups Human impact estimate for Lynch Cove: mg/l Roughly aligns with EPA/Ecology box model range using best estimate inputs 26

27 Findings Are oxygen conditions worsening? Not compared to pre-1900 conditions No evidence of human signal unique to Hood Canal Are septics contributing to fish kills? No, fish kills are natural phenomena; septics are not a significant factor Do oxygen impacts violate water quality standards? Not in the main arm Inconclusive in Lynch Cove/Lower Hood Canal How do impacts vary across the whole of Hood Canal? Where are impacts highest? Impacts increase in inland direction Greatest potential impact in Lynch Cove How certain is the science? Reasonably certain for main arm Inconclusive for Lynch Cove 27

28 Stewardship of Hood Canal Recent wastewater investments make sense Address bacteria problems that contaminate shellfish beds Examples: PIC programs and Belfair WWTP These wastewater investments will also reduce nitrogen (secondary benefit). While not the cause of fish kills, human sources of nitrogen should continue to be monitored and managed, especially in Lynch Cove 28

29 What about Oakland Bay? How can we apply information from Hood Canal? Hood Canal report does not mean or imply any of these: Dissolved oxygen isn t really a problem Nutrients from humans aren t a problem anywhere in Puget Sound Onsite sewage systems aren t a problem anywhere in Puget Sound PIC programs aren t needed We shouldn t bother reducing nutrients anywhere around Puget Sound Screening-level tools aren t helpful Modeling tools aren t worth it No action is needed to save Puget Sound (and Hood Canal and Oakland Bay) 29

30 Dissolved Oyxgen (mg/l) Dissolved oxygen is a problem in some places Measurements confirm low oxygen occurs around Puget Sound, including Hood Canal Difficulty is in determining how much humans worsen DO need complex modeling tools OAK004 long-term monitoring in Oakland Bay Raw Corrected Percentile occurrence 30

31 We don t know if, where, or when nutrients from humans are a problem around Puget Sound South Puget Sound model in progress Do human nutrients violate water quality standards? Budd Inlet submodel Human nutrient sources cause DO impacts as much as 0.5 mg/l Point and nonpoint sources within Budd Inlet and beyond With Capitol Lake Dam 2.5 mg/l Oakland Bay?? South Sound will help, but not optimized for Oakland Bay Effect of the human sources with dam out on minimum DO 31

32 Onsites are a problem in at least some regions of Puget Sound 2008 approved 303(d) listings fecal coliform bacteria 2010 submitted 303(d) listings now category 4A (TMDL) 32

33 PIC or comparable programs are critical tools to manage nonpoint sources Multiple benefits bacteria, nutrients, other Constant vigilance approach Identify using data Isolate source working with property owners Fix the problem Retest to confirm using data Hood Canal nitrogen example 60 mg/l background concentrations 33

34 Reducing nutrients (nitrogen and phosphorus) is needed for multiple reasons Groundwater is unhealthy to drink in some regions due to nitrogen contamination (blue baby syndrome) Many lakes suffer extensive algae blooms due to high phosphorus loads Nutrients often associated with bacteria contamination (same source) Oakland Bay nearshore? 34

35 Screening tools can provide initial estimates of relative impacts due to humans Proportional calculations like those done for Lynch Cove can identify what we do and don t know and what factors cause the greatest uncertainty Oakland Bay *draft* information do not cite or quote Human = part of 168 MT/yr (assume half?) = 4.5 to 16.9% Marine = 1120 MT/yr = 82.8% Atmospheric = MT/yr Shellfish = MT/yr Local importance? Puget Sound: Marine = 86% 35

36 Three-dimensional models are fundamental decisionsupport tools South Puget Sound and Puget Sound-wide models Helpful to understand more detailed patterns Circulation Temperature Salinity Dissolved oxygen Nutrient concentrations and responses Oakland Bay may not be well represented Optimized for deeper waters like Carr and Case Two sharp bends in Hammersley Inlet can t be modeled easily 36

37 Straightened bends let water in and out faster than actually occurs water surface elevations lag in model Source: draft SPS circulation report 37

38 Oakland Bay summer temperatures some of the highest in Puget Sound Source: draft SPS circulation report 38

39 Oakland Bay slowly exchanges with the rest of South Sound Source: draft SPS circulation report 39

40 Action is needed throughout Puget Sound and is happening in Oakland Bay Focus on shoreline onsite sewage systems and bacteria make sense and have multiple benefits Analyses such as those done for Hood Canal inform where you can and cannot influence an outcome We can t do everything everywhere, so where will we make the biggest difference? Both prevention/preservation and restoration are needed in Oakland Bay and throughout Puget Sound What are the priorities, opportunities, and challenges in Oakland Bay? 40

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42 Hood Canal Science Summary Acknowledgements Joel Baker, Puget Sound Institute Corrine Bassin, University of Washington Jill Brandenberger, Pacific Northwest National Lab Mike Brett, University of Washington Michael Cox, EPA Al Devol, University of Washington John Eliasson, Washington Dept. of Health Amy Georgeson, Mason County Keith Grellner, Kitsap County Julie Horowitz, Hood Canal Coordinating Council Andy James, Puget Sound Institute Mitsuhiro Kawase, University of Washington Rochelle Labiosa, EPA John Mickett, University of Washington Jan Newton, University of Washington Tony Paulson, USGS Greg Pelletier, Washington State Dept of Ecology Jeff Richey, University of Washington Brandon Sackmann, Washington Dept. of Ecology Rich Sheibley, USGS Mark Warner, University of Washington Independent Review Panel: Alexandria Boehm, Stanford University Paul Harrison, University of British Columbia James O Donnell, University of Connecticut Hans Paerl, University of North Carolina Harvey Seim, University of North Carolina Ivan Valiela, Marine Biological Laboratory, Woods Hole 42

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44 Source: 44

45 Shoreline Onsite Sewage Systems (OSS) Shoreline OSS not captured in tributary sampling Must estimate this additional nitrogen loading 45

46 5. What are the next steps? November 14: Stakeholder comment period ends December January: Finalize report HCCC works with stakeholders on next steps for scientific analysis and regulatory activity Scoping of future science work to close the uncertainty gaps 46